Control apparatus and control method

ABSTRACT

A control apparatus for controlling an X-ray irradiation area, in which an acquisition circuit acquires information relating to an effective area of a sensor, and a control circuit controls the X-ray irradiation area based on the information relating to the effective area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application IS A Continuation of U.S. application Ser. No.12/580,833, filed Oct. 16, 2009, which claims priority from JapanesePatent Application No. 2008-268864 filed Oct. 17, 2008, which are herebyincorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a control apparatus and a controlmethod for controlling an X-ray irradiation area.

2. Description of the Related Art

Recently, in the field of X-ray imaging for medical use, with theprogress of digital technology, digital X-ray imaging apparatuses usingvarious methods have spread. An example of such an apparatus is acomputed radiography (CR) apparatus, which forms a latent image of anX-ray intensity distribution on a photo-stimulable phosphor, excites thelatent image by laser scanning this photo-stimulable phosphor, and readsthe generated fluorescence by a photomultiplier tube.

Further, digital X-ray imaging apparatuses have been developed whichdirectly digitize the X-ray image without going through an opticalsystem, by using a flat panel detector (FPD). The FPD is an X-ray flatdetection device in which a phosphor is closely attached to a largesurface area amorphous silicon (a-Si) sensor. In addition, FPDs havealso been developed which convert X-rays into electrons by directphotoelectric conversion using amorphous selenium (a-Se), galliumarsenide (GaAs), cadmium telluride (CdTe), lead iodide (PbI2), andmercury iodide (HgI2).

However, in a digital X-ray imaging apparatus which uses such an FPD,calibration typically is performed to correct the characteristics of thesensor due to unevenness in the sensitivity of each photoelectricconversion element and unevenness in the gain in the read circuit(hereinafter referred to as “gain correction”).

The term calibration refers to the acquisition of correction data byirradiating the whole sensor surface roughly with uniform X-rays andperforming imaging (this correction data is hereinafter referred to as“calibration data”). Further, the gain correction is performed bydividing (or logarithmically converting and then subtracting) thecalibration data by the actually captured image of a subject (this imageis hereinafter referred to as “captured image”).

However, in the above calibration, when appropriate calibration data isnot acquired, the gain correction may not be correctly performed. Forexample, when the X-ray irradiation area is limited during calibrationto an area which is narrower than the whole sensor surface, at some ofthe calibration data areas, data which is roughly uniformly irradiatedwith X-rays cannot be obtained. Therefore, the gain correction cannot becorrectly performed at some of the areas of the corresponding capturedimage. Further, when some kind of foreign substance is present betweenthe X-ray tube and the sensor during calibration, a foreign substanceshadow is included in the calibration data. Consequently, the gaincorrection similarly cannot be correctly performed at some of the areasof the captured image.

Various proposals have been made as a method for resolving such issues.For example, Japanese Patent Application Laid-Open No. 2000-070261discusses a method which detects the X-ray irradiation area from thecalibration data, and issues a warning when the whole sensor surface isnot irradiated with the X-rays. In this method, the fact that the X-rayirradiation area is not appropriate can be clearly notified to anoperator by issuing the warning, and an operator is prompted to acquireappropriate calibration data.

Japanese Patent Application Laid-Open No. 63-18172 discusses a methodwhich detects the position of a head during calibration, andautomatically retracts the head when the head is between the X-ray tubeand the sensor. In this method, the inclusion of the shadow of the head,which is a foreign substance, in the calibration data can be avoided,and appropriate calibration data can be acquired.

Japanese Patent Application Laid-Open No. 2001-351091 discusses a methodwhich performs capturing images a plurality of times during calibration,checks the dose, irradiation area, and whether a foreign substance isincluded from the plurality of acquired data, and notifies the operatorof those results. In this method, the dose, irradiation area, andwhether there is no inclusion of foreign substances can be clearlynotified to the operator, and the operator can be prompted to acquireappropriate calibration data.

When performing the above calibration, there are cases where for somereason the whole sensor surface cannot be irradiated with the X-rays.For example, a sufficient distance may not be obtained between the X-raytube and the sensor, or due to design restrictions, a foreign substancewhich is present between the X-ray tube and the sensor may shield theperiphery of the sensor.

In such cases, it is difficult to acquire the appropriate calibrationdata. Consequently, the operator may start imaging as is even if therewas a warning. Thus, when imaging the subject under these conditions, anon-effective area is present where gain correction is not correctlyperformed at some areas of the captured image. However, in theconventional methods, there is no method which allows the operator toconfirm beforehand such a non-effective area in the captured image.Therefore, imaging may be performed while the operator does not realizethat the area of interest used for diagnosis is included in thisnon-effective area. Further, from the standpoint of protecting thesubject from exposure, imaging the subject by irradiating the wholesensor surface with X-rays although the non-effective area is present,may be an issued.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a control apparatusincludes an acquisition unit configured to acquire information relatingto an effective area of a sensor, and a control unit configured tocontrol an X-ray irradiation area based on the acquired information.

Further features and aspects of the present invention will becomeapparent from the following detailed description of exemplaryembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate exemplary embodiments, features,and aspects of the invention and, together with the description, serveto explain the principles of the invention.

FIG. 1 is a configuration diagram of an entire X-ray imaging apparatusaccording to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing order of a calibrationoperation according to an exemplary embodiment of the present invention.

FIG. 3 is a flowchart illustrating a processing order of an imagingoperation according to an exemplary embodiment of the present invention.

FIG. 4 illustrates a method for setting an effective area of a sensoraccording to an exemplary embodiment of the present invention.

FIG. 5 illustrates a method for calculating an X-ray irradiation areaaccording to an exemplary embodiment of the present invention.

FIGS. 6A and 6B illustrate a method for correcting an X-ray irradiationarea according to an exemplary embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the inventionwill be described in detail below with reference to the drawings.

FIG. 1 illustrates an entire X-ray imaging apparatus according to anexemplary embodiment of the present invention.

The present invention is applied to an X-ray imaging apparatus 100 likethat illustrated in FIG. 1, for example. The X-ray imaging apparatus 100has a function for outputting a captured image acquired by exposing asubject to X-rays on a film or an image display device 118. An X-raygeneration apparatus 101 (e.g. X-ray generation circuit) includes anX-ray tube 102 which apply an X-ray beam 107 on a light receivingsurface of a two-dimensional X-ray sensor 109 under the control of anX-ray control circuit 104. The X-ray generation apparatus 101 alsoincludes a collimator 103 for controlling the X-ray irradiation areairradiated by the X-ray tube 102. The position of the collimator 103 iscontrolled by a control circuit 105 (i.e., collimator control circuit).The X-ray imaging apparatus 100 also includes a collimator operationunit 106 (e.g., collimator setting circuit) for inputting informationrelating to the position of the collimator into the control circuit 105.The collimator operation unit 106 has an operation unit such as a dialor operating lever (not illustrated).

The two-dimensional X-ray sensor 109 acquires an analog image signal byperforming a photoelectric conversion based on a two-dimensionalintensity distribution of the X-rays irradiated from the X-raygeneration apparatus 101.

A data collection circuit 110 converts the analog image signal acquiredby the two-dimensional X-ray sensor 109 into a digital image signal(also called “image data”), and supplies the digital image signal toeach circuit under control of a central processing unit (CPU) 115 via aCPU bus 121.

An acquisition circuit 111 acquires an effective area of the sensor frominformation relating to the X-ray irradiation area during calibration.

A determination circuit 113 determines whether the collimator positionis appropriate based on the position of the collimator 103 and theeffective area. A warning circuit 114 issues a warning when it isdetermined by the determination circuit 113 that the collimator positionis not appropriate.

The CPU 115 controls the whole operations of the X-ray imaging apparatus100 based on operations in an operation panel 117 according to a programstored in a main memory 116.

The X-ray imaging apparatus 100 also includes the image display device118, a pre-processing circuit 119, and an image processing circuit 120.These units are connected to each other via the CPU bus 121 so that theyare capable of transferring data.

In such an X-ray imaging apparatus 100, the main memory 116 stores thevarious kinds of data which are used for the processing by the CPU 115.In addition, the main memory 116 functions as a working memory of theCPU 115. The CPU 115 controls the operations of the whole apparatusbased on operations in the operation panel 117 using the main memory116.

The X-ray control circuit 104 controls the X-rays irradiated from theX-ray tube 102 by adjusting tube current, tube voltage, and irradiationtime. The control circuit 105 controls the X-ray irradiation area byadjusting a diaphragm amount of the collimator 103. The control circuit105 also has a CPU 130 (not illustrated) and operates based on a programstored in a memory 140 (not illustrated). The memory 140 stores thevarious kinds of data used for the processing by the CPU 130. Inaddition, the memory 140 functions as a working memory of the CPU 130.By using the memory 140, the CPU 130 controls the operations of thecollimator 103, acquisition circuit 111, determination circuit 113, andwarning circuit 114 based on operations in the collimator operation unit106. A CPU 115 can also control operations by receiving control from asynergistic processing unit (SPU).

The two-dimensional X-ray sensor 109 acquires the analog image signal byperforming a photoelectric conversion based on the two-dimensionalintensity distribution of X-rays irradiated from the X-ray generationapparatus 101. The data collection circuit 110 converts the analog imagesignal acquired by the two-dimensional X-ray sensor 109 into a digitalimage signal, and supplies the digital image signal to each circuitunder control of the CPU 115 via the CPU bus 121.

FIG. 2 is a flowchart illustrating a calibration flow according to anexemplary embodiment of the present invention.

FIG. 3 is a flowchart illustrating an imaging operation flow accordingto an exemplary embodiment of the present invention.

The operations in the calibration and imaging according to the presentexemplary embodiment having the above-described configuration will nowbe described in more detail using the flowcharts of FIGS. 2 and 3.

The operations in the calibration of the X-ray imaging apparatus 100illustrated in FIG. 1 will be described using FIG. 2. First, in stepS201, the operator (X-ray technician etc.) sets the imaging conditions,such as imaging distance, tube voltage, tube current, and irradiationtime, via the operation panel 117.

Next, in step S202, the operator sets the diaphragm amount via thecollimator operation unit 106. At this point, selection can be madebetween a first mode in which a brake is applied and a second mode inwhich a brake is not applied on the operations by the collimatoroperation unit 106.

When the first mode is selected, the brake is applied on the operationsof the collimator operation unit 106 based on a signal output from thecontrol circuit 105. On the other hand, when the second mode isselected, a brake is not applied on the operations of the collimatoroperation unit 106. Whether the first mode or the second mode isselected is determined by the control circuit 105.

During calibration, the non-brake-applying second mode is selected.

The set diaphragm amount is sent to the control circuit 105. The controlcircuit 105 operates the collimator 103 based on the set diaphragmamount. The collimator 103 has a rectangular shape, in which therespective open/closed amounts can be set in the vertical and horizontaldirections by the collimator operation unit 106. The area where theX-rays are irradiated on the two-dimensional X-ray sensor 109 can beconfirmed using visible light (not illustrated) from a lamp or the like.

In step S203, the operator confirms the X-ray irradiation area withvisible light irradiated on the two-dimensional X-ray sensor 109. If theX-ray irradiation area is not appropriate (NO in step S203), theprocessing returns to step S202, and the diaphragm amount is readjusted.While in the calibration the diaphragm amount is adjusted so that theX-rays are irradiated on the whole surface of the two-dimensional X-raysensor 109, if for some reason the X-rays cannot be irradiated on thewhole surface, the diaphragm amount is adjusted so that the X-rays areirradiated over as wide an area as possible.

Next, in step S204, X-ray imaging is started in a state where a subject108 is not present by pressing an exposure button (not illustrated). Inthe X-ray imaging, the X-ray control circuit 104 controls the X-ray tube102 to irradiate with the X-ray beam 107. The irradiated X-ray beam 107reaches the two-dimensional X-ray sensor 109, where it is converted intoa digital image signal by the data collection circuit 110. This digitalimage signal is then supplied to the pre-processing circuit 119. Thecontrol circuit 105 sends the collimator position and the irradiationarea to the data collection circuit 110 when the exposure button (notillustrated) is pressed.

In step S205, the pre-processing circuit 119 performs offset correctionand defect correction on the digital image signal supplied from the datacollection circuit 110. This digital image signal which was subjected topre-processing by the pre-processing circuit 119 is stored in the mainmemory 116 as image data for calibration. Further, a reduced image orimage data on which correction processing was not performed may also bestored in the main memory 116 as image data for calibration.

Although according to the present exemplary embodiment, the calibrationdata is acquired in one imaging, the present exemplary embodiment is notlimited to this. For example, a plurality of calibration data may alsobe acquired by repeating the operations of steps S204 and S205 aplurality of times. Further, one piece of calibration data may be storedin the main memory 116 by averaging the plurality of calibration data.

Next, in step S206 (set effective area), the area where the X-rays wereroughly uniformly irradiated is acquired as the effective area by theacquisition circuit 111, and the effective area information is stored inthe main memory 116. The method for setting the effective area is notespecially limited. For example, as illustrated in FIG. 4, the effectivearea may be set by displaying the calibration data on the image displaydevice 118 and allowing the operator to set an effective area 402 on thetwo-dimensional X-ray sensor illustrated by a solid line with a touchpanel or a mouse from among a sensor imaging area 401 illustrated by asolid line. Further, in step S206, as described above, the position ofthe collimator 103 when the exposure button (not illustrated) waspressed may be stored in the main memory 116 as information about theeffective area.

The irradiated area may also be automatically recognized. An example ofa method for automatically recognizing the irradiated area is to extractthe area in which the X-rays are being directly irradiated on the lightreceiving surface of the two-dimensional X-ray sensor, as theirradiation area by image processing. In this case, the area in whichthe X-rays are being directly irradiated on the light receiving surfaceof the two-dimensional X-ray sensor may be set as the effective area ofthe two-dimensional X-ray sensor. Such an image processing method isknown in the art, and thus a detailed description thereof is omittedhere. For example, the irradiation area can be automatically recognizedby awarding points for field edge similarity based on a pattern of apixel of interest and the pixel values of the pixels surrounding thatpixel.

The image to be used can be a reduced image stored in the main memory116 or image data on which correction processing was not performed.

The imaging operations in the X-ray imaging apparatus 100 illustrated inFIG. 1 will now be described using FIG. 3. First, in step S301, theoperator positions the subject 108 at an appropriate position relativeto the two-dimensional X-ray sensor 109 and sets the imaging conditions,such as imaging distance, tube voltage, tube current, and irradiationtime, via the operation panel 117.

In step S302, if the non-brake-applying second mode is selected, theoperator sets the diaphragm amount via the collimator operation unit 106based on a type of the subject body and a test. The set diaphragm amountis sent to the control circuit 105. Further, the control circuit 105operates the collimator 103 based on the set diaphragm amount, andstores the diaphragm amount in the main memory 116. The collimator 103has a rectangular shape, in which the respective open/closed amounts canbe set in the vertical and horizontal directions by the collimatoroperation unit 106.

Next, the control circuit 105 reads from the main memory 116 the setdiaphragm amount of collimator operation unit 106 and the informationabout the effective area set during calibration, and determines whetherthe X-ray irradiation area is not larger than the effective area. First,in step S303 (calculate irradiation area based on diaphragm amount), theX-ray irradiation area in the image acquired by the two-dimensionalX-ray sensor 109 is calculated from the diaphragm amount of thecollimator operation unit 106. As a method for calculating theirradiation area from the diaphragm amount, a method described inJapanese Patent Application Laid-Open No. 2000-210273 may be used. Forexample, when calculating the irradiation area in the upward direction,as illustrated in FIG. 5, if a distance 504 from an X-ray tube 501 to asensor 505 is d (cm), and an open angle 503 in the upward direction isa, the irradiation area in the upward direction can be calculated by thefollowing equation (1) as an offset amount (Au) (pixel) from a sensorcenter 506 of the sensor 505. The irradiation areas in the downward andleft/right directions may be calculated in a similar manner.Au=d×tan(a)/p  (1)

Here, p is the image size (cm) of the sensor. Obviously, the effectivearea can also be determined from the position of the collimator 103stored during calibration.

Next, in step S304, the size of the irradiation area and the effectivearea are compared. If the irradiation is smaller than the effectivearea, then the process goes to step 307. Otherwise, the process proceedsto step S305. For example, when at least one side of an irradiation area602 in FIG. 6A indicated by a solid line is set (set irradiation area602) to be wider than a sensor effective area 601 indicated by a dottedline (the right direction in FIG. 6A), in step S305, the diaphragmamount is adjusted like in FIG. 6B so that the irradiation area(adjusted irradiation area 603) is not wider than the sensor effectivearea 601. Further, in step S306 (display warning), a warning that theirradiation area was set to be wider than the effective area is sent tothe operator by the warning circuit 114.

When the first mode is selected, a brake is applied on the operations ofthe collimator operation unit 106 by an output signal of the controlcircuit 105. For example, when the operations of the collimatoroperation unit 106 are performed via a mechanical operation such as theone performed with a dial or a switch, a mechanical brake is appliedwith information relating to the effective area as a reference. Thebrake is applied by the control circuit 105 so that the force used foroperation increases as the X-rays which should be output from thecollimator approach the effective area.

Further, when the operations of the collimator operation unit 106 arenot made via a mechanical operation, but are made via an input operationusing a touch panel or the like, the range of the movement amount of thecollimator is changed based on the amount of the input operation withthe effective area as a reference. The brake is applied by the controlcircuit 105 so that the movement amount with respect to the operationdecreases as the X-rays which should be output from the collimatorapproach the effective area.

When the second mode is selected, in step S307, the operator can alsoconfirm the X-ray irradiation area by visible light irradiated on thetwo-dimensional X-ray sensor 109. If the X-ray irradiation area is notappropriate (NO in step S307), the processing returns to step S302, andthe diaphragm amount is readjusted. In such a case, a brake from thecontrol circuit 105 is not applied via the collimator operation unit106.

After the diaphragm adjustment is finished, in step S308, the operatorpresses an exposure button (not illustrated) to start X-ray imaging. Inthe X-ray imaging, the X-ray control circuit 104 controls the X-ray tube102 to irradiate with the X-ray beam 107. The irradiated X-ray beam 107is transmitted attenuating through the subject 108, and reaches thetwo-dimensional X-ray sensor 109, where it is converted into a digitalimage signal by the data collection circuit 110. This digital imagesignal is then supplied to the pre-processing circuit 119.

In step S309, the pre-processing circuit 119 performs offset correctionand defect correction on the digital image signal supplied from the datacollection circuit 110. Further, in step S309, the pre-processingcircuit 119 reads the calibration data from the main memory 116, andperforms gain correction. The gain correction can be performed bydividing (or logarithmically converting and then subtracting) thecalibration data by the acquired digital image signal. This digitalimage signal which was subjected to pre-processing by the pre-processingcircuit 119 is stored in the main memory 116 as the captured image, andsupplied to the image processing circuit 120.

In step S310, processing for converting the captured image into an imagesuitable for diagnosis is performed by the image processing circuit 120.For example, processing such as increasing sharpness, dynamic rangecompression, noise reduction, and gradation conversion is performed. Themethod for each processing item is not especially limited. For example,already known methods may be used, such as the one using an unsharp maskimage (Japanese Patent Application Laid-Open No. 2002-374418), producingan image with a plurality of frequency components by wavelet conversionor Laplacian pyramid decomposition, and then performing processing(Japanese Patent Application Laid-Open No. 2003-076992), and gradationconversion by an S-shaped curve (Japanese Patent Application Laid-OpenNo. 11-088688). Not all of these processing items have to be performed.For example, only the processing set by the operation panel 117 may beselectively performed.

In the present exemplary embodiment, the operator can clearly confirm anon-effective area from a warning which is displayed when the collimatoris set for a non-effective area of the sensor. In the non-effectivearea, gain correction is not correctly performed before imaging.Further, the subject can be thoroughly protected from exposure byautomatically limiting the collimator so that X-rays are not irradiatedon such a non-effective area.

As described above, the X-ray irradiation area can be controlled evenwhen the X-rays are not irradiated on the entire light receiving surfaceof the sensor during calibration.

The present invention may also use a recording medium on which asoftware program code for realizing the functions of the above exemplaryembodiment is recorded. More specifically, the present invention is alsoachieved by supplying a recording medium to a system or an apparatus,and having a computer (or a CPU or a micro processing unit (MPU)) of thesystem or apparatus read and execute the program code stored in therecording medium. In this case, the program code itself read from therecording medium realizes the functions of the above exemplaryembodiment, so that the recording medium on which the program code isrecorded constitutes the present invention.

Examples of storage media which can be used for supplying the programcode include a flexible disk, a hard disk, an optical disk, amagneto-optical disk, a compact disc read only memory (CD-ROM), a CD-R,a magnetic tape, a nonvolatile memory card, a ROM and the like.

Further, the present invention also includes embodiments where, based onan instruction from the program code, an operating system (OS) or thelike running on the computer performs part or all of the actualprocessing, and by that processing the functions of the above-describedexemplary embodiment are realized.

Further, the present invention also includes cases where the programcode read from the recording medium is written into a memory provided ona function expansion board inserted into the computer or a functionexpansion unit connected to the computer. In such a case, based on aninstruction from the program code, a CPU or the like provided on thefunction expansion board or function expansion unit performs part or allof the actual processing, and by that processing the functions of theabove-described exemplary embodiment are realized.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures, and functions.

What is claimed is:
 1. A control apparatus for controlling a collimatorconfigured to limit an area of an X-ray generated by an X-ray generationapparatus, the control apparatus comprising: an operation unit in whichan operator inputs a diaphragm amount of the collimator; an acquisitionunit configured to acquire information relating to an effective area ofa sensor; and a control unit configured to brake operations of acollimator operation unit based on the effective area acquired by theacquisition unit in a case where a first mode is selected, and not tobrake operations of the collimator operation unit based on the effectivearea in a case where a second mode is selected.
 2. The control apparatusaccording to claim 1, wherein the operation unit inputs the diaphragmamount by a mechanical operation, and wherein the control unit controlsthe collimator so that a braking force of the mechanical operationincreases as an X-ray to be emitted from the collimator approaches theeffective area.
 3. The control apparatus according to claim 1, whereinthe operation unit is a touch panel, and wherein the control unitcontrols the collimator so that a moving amount of the collimator to beinstructed with the touch panel decreases as an area of an X-ray to beemitted from the collimator approaches the effective area.
 4. Thecontrol apparatus according to claim 1, wherein the effective area isacquired based on an X-ray irradiation area during calibration.
 5. Thecontrol apparatus according to claim 1, wherein the effective area isacquired based on a distance between an X-ray irradiation area in animage acquired from a sensor and an X-ray tube irradiating the sensorwith the X-ray.
 6. The control apparatus according to claim 1, whereinthe effective area is acquired based on a position of the collimator. 7.The control apparatus according to claim 4, further comprising: adetermination unit configured to determine whether a position of thecollimator is appropriate based on information relating to the positionof the collimator and the effective area; and a warning unit configuredto issue a warning when the determination unit determines that theposition of the collimator is not appropriate.
 8. The control apparatusaccording to claim 1, further comprising: a determination unitconfigured to determine whether a position of the collimator isappropriate based on information relating to the position of thecollimator and the effective area, wherein the control unit isconfigured to limit a movement range of the collimator based on thedetermination of the determination unit.
 9. A control method forcontrolling a collimator configured to limit an area of X-ray generatedby an X-ray generation apparatus, the control method comprising:inputting a diaphragm amount of the collimator by an operator; acquiringinformation relating to an effective area of a sensor; and controllingthe collimator based on the effective area acquired in the acquisitionstep in a case where a first mode is selected, and to control thecollimator according to an operation of an operation unit and thencontrol the collimator based on the effective area acquired by theacquisition unit in a case where a second mode is selected.
 10. Acomputer-readable storage medium storing a computer program for causinga computer to execute the control method according to claim
 9. 11. Acontrol apparatus for controlling a collimator configured to limit anarea of an X-ray generated by an X-ray generation apparatus, the controlapparatus comprising: an operation unit in which an operator inputs adiaphragm amount of the collimator; an acquisition unit configured toacquire information relating to an effective area of a sensor; and acontrol unit configured to control the collimator according to anoperation of the operation unit and then notify the operator of theeffective area according to the operation of the operation unit based onthe effective area acquired by the acquisition unit.
 12. A controlapparatus for controlling a collimator configured to limit an area of anX-ray generated by an X-ray generation apparatus, the control apparatuscomprising: an operation unit in which an operator inputs a diaphragmamount of the collimator; an acquisition unit configured to acquireinformation relating to an effective area of a sensor; and a controlunit configured to apply a brake on an operation of the operation unitbased on the effective area acquired by the acquisition unit in a casewhere a first mode is selected, and not to apply a brake on theoperation of the operation unit and then control the collimator based onthe effective area acquired by the acquisition unit in a case where asecond mode is selected.
 13. A control apparatus for controlling acollimator configured to limit an area of an X-ray generated by an X-raygeneration apparatus, the control apparatus comprising: an operationunit in which an operator inputs a diaphragm amount of the collimator;an acquisition unit configured to acquire information relating to aneffective area of a sensor; and a control unit configured to control thecollimator according to an operation of the operation unit and thencontrol the collimator based on the effective area acquired by theacquisition unit.
 14. A control apparatus for controlling a collimatorconfigured to limit an area of an X-ray generated by an X-ray generationapparatus, the control apparatus comprising: an operation unit in whichan operator inputs a diaphragm amount of the collimator; an acquisitionunit configured to acquire information relating to an effective area ofa sensor; and a control unit configured to brake operations of acollimator operation unit based on the effective area acquired by theacquisition unit.
 15. A control apparatus for controlling a collimatorconfigured to limit an area of an X-ray generated by an X-ray generationapparatus, the control apparatus comprising: an acquisition unitconfigured to acquire a collimator position during calibration of asensor; and a control unit configured to limit the collimator movementbased on the collimator position.
 16. A control method for controlling acollimator configured to limit an area of an X-ray generated by an X-raygeneration apparatus, the control method comprising: acquiring acollimator position during calibration of a sensor; and limiting thecollimator movement based on the collimator position.
 17. The apparatusaccording to claim 15, wherein the calibration is an acquisition ofcorrection data to correct a gain of the sensor by irradiating a partialarea of the sensor surface through the collimator.